♪ Believe it or not, tiny Columbus, Indiana, in south central Bartholomew County, is considered one of the most architecturally significant cities in the United States.

And that's thanks largely to J. Irwin Miller, the former head of the Cummins Engine Company, based right here in Columbus.

In 1954, Miller established the Cummins Foundation, and offered to pay the hefty architectural fees for new public buildings.

That allowed the city to enlist premier architects such as IM Pei, Eero and Eliel Saarinen, Kevin Roche, Harry Weese and others.

Today, visitors can easily glimpse many of the resulting architectural treasures on a Columbus Area Visitors Center walking tour.

>> It is unique and remarkable, really, that we have over 70 significant buildings in this -- and landscapes in this town of 50,000 or so.

>> John Crofts would certianly know.

As an architectural tour guide for the past eight years, he's been around the block, literally.

>> On the walking tour, we'll go past many sites, and probably stop and talk about well over a dozen.

We see a mix of mid-century modern, even some more recent buildings, but then also some of the vernacular buildings, the courthouse, the historic city hall and that.

>> The tours are geared towards tourists and locals alike, ensuring that both gain a better understanding of the city's architecture and history.

>> We have locals that have actually moved here and been here for a while, but have never bothered to take a tour or don't fully understand kind of the back story to why we have all this modern architecture.

>> There are, of course, some locations that stand out more than others.

>> As far as the tours, it seems like the Miller house, the modern house which is now a museum, that seems to be our most popular tour.

We've got a lot of fabulous churches.

So I think those are a draw.

My favorite place is a coffee shop that was in a modern bank branch.

It's just great to be in that space and enjoy time there.

>> The addition doesn't touch the building.

It's connected with a glass atrium.

So IM Pei's vision of the natural lighting and that is all preserved.

>> For John, these tours are a labor of love.

>> I got involved with the visitors center after I retired, 37 years at Cummins.

I'm a mechanical engineer.

So work-wise, this was sort of a change, if you will, for me.

>> It's just the names and the dates.

>> What I enjoy about giving tours is the opportunity to meet people, and, I guess I kind of like to tell stories and talk a lot.

>> I learned that there's a workman's boot hiding on the sculpture.

>> You know, you really feel good if you can answer their questions and give them an appreciation for what they are seeing.

>> And while Columbus may not wow you like other major architectural destinations, Columbus will certainly surprise you.

>> The reason that people might want to visit Columbus and then take a tour is to see what can happen when there's sort of a focus.

It was sort initiated by Irwin Miller, but then the whole community seems to have caught on.